JP4211920B2 - Organic electroluminescence device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an organic electroluminescent element (light emitting element or EL element) that can emit light by converting electric energy into light.
[0002]
[Prior art]
Today, research and development on various display elements are active. Among them, organic electroluminescence (EL) elements are attracting attention as promising display elements because they can emit light with high luminance at a low voltage.
[0003]
In recent years, the active application of organic EL elements to color displays, white light sources, etc. has been actively studied, but in order to develop high-performance color displays and white light sources, the characteristics of blue, green, and red light-emitting elements. It is necessary to improve. Further, as an element that emits blue light, an element containing a butadiene derivative such as tetraphenylbutadiene is known (Patent Document 1), but improvement is required because the maximum luminance and the light emission efficiency are low.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 5-94875
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a multicolor light emitting device having good light emitting characteristics.
[0006]
[Means for Solving the Problems]
AboveThe objective was achieved by the following means.
1. An organic electroluminescence device having at least one organic layer including a light emitting layer between a pair of electrodes, the following general formula (1):
[Chemical formula 5]
(In the general formula (1), R¹¹Represents a substituent and X¹¹, X¹², X¹³And X¹⁴Each represents a nitrogen atom or a substituted or unsubstituted carbon atom;¹¹Represents a metal ion and n¹¹And n¹²Each represents 0 or 1 and n¹¹N is 1¹²Is 0. ) Is contained in the organic layer.
2. The compound represented by the general formula (1) is represented by the following general formula (2):
[Chemical 6]
(In the general formula (2), R²¹, R²²And R²³Each represents a substituent,X ²² and X ²³ Each represents an unsubstituted carbon atom.2. The organic electroluminescent element according to 1, which is a compound represented by
3. The compound represented by the general formula (1) is represented by the following general formula (3):
[Chemical 7]
(In general formula (3), R³¹, R³²And R³³Each represents a substituent, and X³²And X³³Each represents a nitrogen atom or a substituted or unsubstituted carbon atom. 2. The organic electroluminescent element according to 1, which is a compound represented by
4). The compound represented by the general formula (1) is represented by the following general formula (4):
[Chemical 8]
(In the general formula (4), R⁴¹, R⁴²And R⁴³Each represents a substituent, and X⁴²And X⁴³Each represents a nitrogen atom or a substituted or unsubstituted carbon atom;⁴¹Represents a metal ion, L⁴¹Represents a ligand, m⁴¹Represents an integer of 1 to 7. 2. The organic electroluminescent element according to 1, which is a compound represented by
[0007]
DETAILED DESCRIPTION OF THE INVENTION
[1] Compounds represented by general formulas (1) to (4)
The general formula (1) will be described. X¹¹, X¹², X¹³And X¹⁴Each represents a nitrogen atom or a substituted or unsubstituted carbon atom. X¹¹, X¹², X¹³And X¹⁴If possible, they may be linked together to form a ring structure (for example, a benzo-fused ring).
[0008]
Examples of the substituent on the carbon atom include an alkyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, such as a methyl group, an ethyl group, and iso-propyl. Group, tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, etc., alkenyl group (preferably having 2 to 30 carbon atoms, more preferably carbon number) 2 to 20, particularly preferably 2 to 10 carbon atoms, such as vinyl group, allyl group, 2-butenyl group, 3-pentenyl group and the like, alkynyl group (preferably 2 to 30 carbon atoms, more preferably carbon number) 2 to 20, particularly preferably 2 to 10 carbon atoms, for example, propargyl group, 3-pentynyl group, etc., aryl groups (preferably 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably carbon atoms) It is number 6-12 For example, a phenyl group, a p-methylphenyl group, a naphthyl group, an anthranyl group, etc.), an amino group (preferably having 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, particularly preferably 0 to 10 carbon atoms, For example, amino group, methylamino group, dimethylamino group, diethylamino group, dibenzylamino group, diphenylamino group, ditolylamino group, etc.), alkoxy group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, especially Preferably it is C1-C10, for example, a methoxy group, an ethoxy group, a butoxy group, 2-ethylhexyloxy group etc.), an aryloxy group (preferably C6-C30, more preferably C6-C20, Particularly preferably, it has 6 to 12 carbon atoms, for example, phenyloxy group, 1-naphthyloxy group, 2-naphthyloxy group, etc., heterocyclic oxy group (preferably carbon number) 1 to 30, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, pyridyloxy group, pyrazyloxy group, pyrimidyloxy group, quinolyloxy group, etc.), acyl group (preferably 1 to 30 carbon atoms) , More preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, acetyl group, benzoyl group, formyl group, pivaloyl group, etc.), alkoxycarbonyl group (preferably having 2 to 30 carbon atoms, more preferably Has 2 to 20 carbon atoms, particularly preferably 2 to 12 carbon atoms. For example, methoxycarbonyl group, ethoxycarbonyl group and the like, and aryloxycarbonyl group (preferably 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms). Particularly preferably, it has 7 to 12 carbon atoms, such as a phenyloxycarbonyl group, etc., an acyloxy group (preferably 2 to 30 carbon atoms, more preferably Alternatively, it has 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, for example, an acetoxy group, a benzoyloxy group, etc., an acylamino group (preferably 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, especially Preferably it is C2-C10, for example, an acetylamino group, a benzoylamino group, etc., alkoxycarbonylamino group (preferably C2-C30, more preferably C2-C20, especially preferably C2-C2 12 such as a methoxycarbonylamino group and the like, an aryloxycarbonylamino group (preferably having a carbon number of 7 to 30, more preferably a carbon number of 7 to 20, particularly preferably a carbon number of 7 to 12, such as phenyloxycarbonyl Amino groups, etc.), sulfonylamino groups (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, Methanesulfonylamino group, benzenesulfonylamino group, etc.), sulfamoyl group (preferably having 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as sulfamoyl group, A famoyl group, a dimethylsulfamoyl group, a phenylsulfamoyl group, etc.), a carbamoyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, A carbamoyl group, a methylcarbamoyl group, a diethylcarbamoyl group, a phenylcarbamoyl group, etc.), an alkylthio group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example methylthio Group, ethylthio group, etc.), arylthio group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms). Particularly preferably, it has 6 to 12 carbon atoms, such as a phenylthio group, etc., a heterocyclic thio group (preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, For example, pyridylthio group, 2-benzimidazolylthio group, 2-benzoxazolylthio group, 2-benzthiazolylthio group, etc., sulfonyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, especially Preferably it has 1 to 12 carbon atoms, such as mesyl group, tosyl group, etc.), sulfinyl group (preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, For example, methanesulfinyl group, benzenesulfinyl group, etc.), ureido group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as ureido group, Luureido group, phenylureido group, etc.), phosphoric acid amide group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as diethyl phosphoric acid amide group, phenyl Phosphoric acid amide group, etc.), hydroxy group, mercapto group, halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino Group, imino group, heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, including nitrogen atom, oxygen atom, sulfur atom and the like as a hetero atom, such as imidazolyl group, pyridyl group, Quinolyl, furyl, thienyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazoli Group, carbazolyl group, azepinyl group, etc.), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, such as trimethylsilyl group, triphenylsilyl group, etc. ), A silyloxy group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms, such as trimethylsilyloxy group, triphenylsilyloxy group). These substituents may be further substituted.
[0009]
X¹¹And X¹⁴Each preferably represents a substituted or unsubstituted carbon atom, more preferably a substituted carbon atom, and still more preferably an aryl group-substituted carbon atom. X¹²And X¹³Each preferably represents a substituted or unsubstituted carbon atom, more preferably an unsubstituted carbon atom. X¹¹And X¹⁴Are each a substituted carbon atom and X¹²And X¹³Are each preferably a substituted or unsubstituted carbon atom, and X¹¹And X¹⁴Are each an aryl group-substituted carbon atom, and X¹²And X¹³It is more preferable that each is an unsubstituted carbon atom.
[0010]
R¹¹Represents a substituent. The substituent is not particularly limited, but is preferably an alkyl group, an alkenyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, etc., more preferably an alkyl group, an aryl group or a heteroaryl group, and an aryl group. Groups are more preferred.
[0011]
M¹¹Represents a metal ion, preferably a transition metal ion. Although the transition metal ion is not particularly limited, iridium ion, platinum ion, rhenium ion, ruthenium ion and the like are preferable, iridium ion or platinum ion is more preferable, and iridium ion is particularly preferable.
[0012]
n¹¹And n^{twenty two}Represents 0 or 1, respectively. n¹¹N is 1¹²Is 0. n¹¹Is preferably 1, n¹²Is preferably 0.
[0013]
The general formula (2) will be described.R ²¹ Is the above R ¹¹ The preferred range is also the same. X ²² And X ²³ Each represents an unsubstituted carbon atom.R²²And R²³Each represents a substituent. R²²And R²³The substituent represented by X is X¹¹~ X¹⁴The group mentioned as a substituent on the carbon atom represented by these is mentioned. R²²And R²³Is preferably an alkyl group, an aryl group, a heteroaryl group or the like, more preferably an aryl group or a heteroaryl group, and even more preferably an aryl group.
[0014]
The general formula (3) will be described. R³¹, R³², R³³, X³²And X³³Are the above R²¹, R²², R²³,X ¹² andX ¹³ The preferred range is also the same.
[0015]
The general formula (4) will be described. R⁴¹, R⁴², R⁴³, X⁴², X⁴³And M⁴¹Are the above R²¹, R²², R²³,X ¹² ,X ¹³ And M¹¹The preferred range is also the same.
[0016]
L⁴¹Represents a ligand. Examples of ligands include, for example, "Photochemistry and Photophysics of Coordination Compounds", Springer-Verlag, H. Yersin, published in 1987, "Organic Metal Chemistry-Fundamentals and Applications", Tatsukabosha, Akio Yamamoto , 1982, etc., preferably halogen ligands (chlorine ligand, fluorine ligand, etc.), nitrogen-containing heterocyclic ligands (bipyridyl ligand, phenanthroline coordination) Ligand, phenylpyridine ligand, pyrazolylpyridine ligand, benzimidazolylpyridine ligand, picolinic acid ligand, thienylpyridine ligand, pyrazolylpyridine ligand, imidazolylpyridine ligand, triazolylpyridine ligand Ligands, pyrazolylbenzoxazole ligands, their condensed rings (phenylquinoline ligands, benzothienylpyridine ligands, biquinoline ligands, etc.), diketone ligands (a) Cetylacetone ligand), nitrile ligand (acetonitrile ligand, etc.), CO ligand, isonitrile ligand (t-butylisonitrile ligand, etc.), phosphorus ligand (phosphine derivative, phosphorus) Acid ester derivatives, phosphinine derivatives, etc.), carboxylic acid ligands (acetic acid ligands, etc.), more preferably diketone ligands or bidentate nitrogen-containing heterocyclic ligands, more preferably acetylacetone. A ligand, a phenylpyridine ligand, a picolinic acid ligand or a condensed ring thereof, particularly preferably a phenylpyridine ligand or a condensed ring thereof.
[0017]
L⁴¹Is R⁴¹, R⁴²Or R⁴³To form a multidentate ligand (phenylphosphol ligand, pyridylphosphol ligand, etc.). m⁴¹Represents an integer of 1 to 7. m⁴¹L for multiple⁴¹May be the same or different. m⁴¹Is preferably 1 to 5, and more preferably 1 to 3.
[0018]
The compounds represented by the general formulas (1) to (4) may be low molecular compounds, oligomer compounds, polymer compounds (weight average molecular weight (polystyrene conversion) is preferably 1000 to 5000000, more preferably 2000 to 1000000, more preferably 3000 to 100000). In the case of a polymer compound, the structure represented by the general formula (1) may be included in the polymer main chain or may be included in the polymer side chain. In the case of a polymer compound, it may be a homopolymer compound or a copolymer. The compounds represented by the general formulas (1) to (4) are preferably low molecular compounds.
[0019]
Compounds represented by general formulas (1) to (4)J. Org. Chem. , 1982, 47, 2376-2379.
[0020]
Compounds represented by general formulas (1) to (4)IsOrganic electroluminescence deviceContained in the organic layer. Here, the organic layer means a layer existing between a pair of electrodes, and specifically, a layer containing at least one of an organic compound and an inorganic compound.
[0021]
nextOrganic electroluminescence deviceAlthough the specific example of the compound represented by General formula (1)-(4) contained in is shown, this invention is not limited to these.
[0022]
[Chemical 9]
[0023]
[Chemical Formula 10]
[0024]
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[0025]
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[0026]
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[0027]
The compounds represented by the general formulas (1) to (4) can be synthesized by various known methods. For example, a phosphole derivative can be synthesized by heating a diene derivative and a dichlorophosphine derivative, and phosphole oxide can be synthesized by oxidizing the phosphole derivative (eg, using hydrogen peroxide, m-chloroperbenzoic acid, etc.). A derivative can be synthesized, and a metal complex having a phosphole ligand can be synthesized by reacting a phosphole derivative with a complex compound.
[0028]
[2] Organic electroluminescence device
The organic electroluminescent element of the present invention isGeneral formula (2) or (3)As long as it is an element that uses a compound represented byGeneral formula (2) or (3)An element using the compound represented by the above as a light emitting material (which may be a fluorescent material or a phosphorescent material) or a hole transport material is preferable, and an element using the light emitting material is more preferable. An organic EL (electroluminescence) element can be mentioned as a typical light emitting element.
[0029]
General formula (2) or (3)0.1-50 mass% is preferable in the light emitting layer of the compound represented by this, 0.5-30 mass% is more preferable, 1-10 mass% is further more preferable.General formula (2) or (3)The content of the compound represented by the formula (1) in the hole transport layer is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, and particularly preferably 90 to 100% by mass.
[0030]
The organic electroluminescent device of the present invention preferably has a layer containing a compound having an ionization potential of 5.9 eV or more (more preferably 6.0 eV or more) between the cathode and the light-emitting layer, and has an electron transport layer having an ionization potential of 5.9 eV or more. More preferably.
[0031]
The formation method of the organic layer containing the compound represented by the general formula (1) is not particularly limited, but resistance heating vapor deposition, electron beam, sputtering, molecular lamination method, coating method (spray coating method, dip coating method, impregnation method) , Roll coat method, gravure coat method, reverse coat method, roll brush method, air knife coat method, curtain coat method, spin coat method, flow coat method, bar coat method, micro gravure coat method, air doctor coat, blade coat method Squeeze coating method, transfer roll coating method, kiss coating method, cast coating method, extrusion coating method, wire bar coating method, screen coating method, etc.), inkjet method, printing method, transfer method and the like can be used. From the viewpoint of characteristics and production, resistance heating vapor deposition, coating method or transfer method is preferred.
[0032]
General formula (2) or (3)Although the formation method of the organic layer containing the compound represented by is not particularly limited, resistance heating vapor deposition, electron beam, sputtering, molecular lamination method, coating method (spray coating method, dip coating method, impregnation method, roll coating method, Gravure coating method, reverse coating method, roll brush method, air knife coating method, curtain coating method, spin coating method, flow coating method, bar coating method, micro gravure coating method, air doctor coating, blade coating method, squeeze coating method, A transfer roll coating method, a kiss coating method, a cast coating method, an extrusion coating method, a wire bar coating method, a screen coating method, etc.), an ink jet method, a printing method, a transfer method and the like can be used. From the viewpoint of characteristics and production, resistance heating vapor deposition, coating method or transfer method is preferred.
[0033]
The anode supplies holes to a hole injection layer, a hole transport layer, a light emitting layer, and the like. As the material for the anode, metals, alloys, metal oxides, electrically conductive compounds, mixtures thereof, and the like can be used, and materials having a work function of 4 eV or more are preferably used. Specific examples include conductive metal oxides such as tin oxide, zinc oxide, indium oxide and indium tin oxide (ITO), metals such as gold, silver, chromium and nickel, and mixtures of these metals and conductive metal oxides. Alternatively, a laminate, an inorganic conductive material such as copper iodide or copper sulfide, an organic conductive material such as polyaniline, polythiophene, or polypyrrole, a laminate of these with ITO, or the like can be given. A conductive metal oxide is preferable, and ITO is particularly preferable from the viewpoints of productivity, high conductivity, transparency, and the like. The thickness of the anode can be appropriately selected depending on the material, but is usually preferably in the range of 10 nm to 5 μm, more preferably 50 nm to 1 μm, and further preferably 100 nm to 500 nm.
[0034]
As the anode, a soda lime glass, non-alkali glass, a transparent resin substrate, or the like formed on the anode material is generally used. When glass is used, it is preferable to use non-alkali glass in order to reduce ions eluted from the glass. When using soda lime glass, it is preferable to use a glass with a barrier coat such as silica. The thickness of the substrate is not particularly limited as long as it is sufficient to maintain the mechanical strength, but when glass is used, it is usually 0.2 mm or more, preferably 0.7 mm or more.
[0035]
Various methods are used for producing the anode depending on the material. For example, in the case of ITO, an electron beam method, a sputtering method, a resistance heating vapor deposition method, a chemical reaction method (sol-gel method, etc.), an indium tin oxide dispersion coating, etc. Use the method. The anode can be driven to lower the driving voltage of the element or increase the light emission efficiency by other processing. For example, in the case of ITO, UV-ozone treatment, plasma treatment, etc. are effective.
[0036]
The cathode supplies electrons to the electron injection layer, the electron transport layer, the light emitting layer, etc., and the adhesion, ionization potential, stability, etc. between the negative electrode and the adjacent layer such as the electron injection layer, the electron transport layer, the light emitting layer, etc. Select with consideration. As a material for the cathode, a metal, an alloy, a metal halide, a metal oxide, an electrically conductive compound, or a mixture thereof can be used. Specific examples include alkali metals (Li, Na, K, etc.) and their fluorides or oxides, alkaline earth metals (Mg, Ca, etc.) and their fluorides or oxides, gold, silver, lead, aluminum, sodium Examples thereof include potassium alloys or mixed metals thereof, lithium-aluminum alloys or mixed metals thereof, magnesium-silver alloys or mixed metals thereof, rare earth metals such as indium and ytterbium. A material having a work function of 4 eV or less is preferable, and aluminum, a lithium-aluminum alloy or a mixed metal thereof, a magnesium-silver alloy or a mixed metal thereof, or the like is more preferable. The cathode may have not only a single layer structure of the above compound and mixture but also a laminated structure containing the above compound and mixture. For example, a laminated structure of aluminum / lithium fluoride, aluminum / lithium oxide or the like is preferable. The thickness of the cathode can be appropriately selected depending on the material, but is usually preferably in the range of 10 nm to 5 μm, more preferably 50 nm to 1 μm, and further preferably 100 nm to 1 μm.
[0037]
An electron beam method, a sputtering method, a resistance heating vapor deposition method, a coating method, a transfer method, or the like can be used for producing the cathode, and a metal can be vapor-deposited alone or two or more components can be vapor-deposited simultaneously. Furthermore, a plurality of metals can be vapor-deposited simultaneously to form an alloy electrode, or a previously prepared alloy may be vapor-deposited. The sheet resistance of the anode and cathode is preferably low, and is preferably several hundred Ω / □ or less.
[0038]
The material of the light emitting layer can inject holes from the anode, the hole injection layer, the hole transport layer, etc. when an electric field is applied, and can inject electrons from the cathode, the electron injection layer, the electron transport layer, etc. In addition, any layer can be used as long as it can form a layer having a function of moving injected charges and a function of emitting light by providing a recombination field of holes and electrons. In addition to these compounds, for example, benzoxazole, benzimidazole, benzothiazole, styrylbenzene, polyphenyl, diphenylbutadiene, tetraphenylbutadiene, naphthalimide, coumarin, perylene, perinone, oxadiazole, aldazine, pyralidine, cyclopentadiene, bis Styrylanthracene, quinacridone, pyrrolopyridine, thiadiazolopyridine, Clopentadiene, styrylamine, aromatic dimethylidin compounds, metal complexes represented by 8-quinolinol metal complexes and rare earth complexes, polymer compounds such as polythiophene, polyphenylene, polyphenylene vinylene, organic silanes, iridium trisphenylpyridine complexes, platinum porphyrins Examples thereof include transition metal complexes represented by complexes and derivatives thereof. Although the film thickness of a light emitting layer is not specifically limited, Usually, the range of 1 nm-5 micrometers is preferable, More preferably, they are 5 nm-1 micrometer, More preferably, they are 10 nm-500 nm.
[0039]
The method for forming the light emitting layer is not particularly limited, but resistance heating evaporation, electron beam, sputtering, molecular lamination method, coating method, ink jet method, printing method, LB method, transfer method, etc. can be used, preferably resistance heating evaporation. Alternatively, a coating method is used.
[0040]
The light emitting layer may be formed of a single compound or a plurality of compounds. In addition, the light emitting layer may be one or plural. For example, each layer may emit light with a different emission color, may emit white light, or may emit white light from a single light emitting layer. May be. When there are a plurality of light emitting layers, each light emitting layer may be formed of a single material or may be formed of a plurality of compounds.
[0041]
The material of the hole injection layer and the hole transport layer has any one of the function of injecting holes from the anode, the function of transporting holes, and the function of blocking electrons injected from the cathode. That's fine. Specific examples include carbazole, triazole, oxazole, oxadiazole, imidazole, polyarylalkane, pyrazoline, pyrazolone, phenylenediamine, arylamine, amino-substituted chalcone, styrylanthracene, fluorenone, hydrazone, stilbene, silazane, aromatic group Tertiary amine compound, styrylamine compound, aromatic dimethylidin compound, porphyrin compound, polysilane compound, poly (N-vinylcarbazole), aniline copolymer, thiophene oligomer, conductive polymer oligomer such as polythiophene, organic Examples thereof include silane, a carbon film, a compound represented by the general formula (1), and derivatives thereof. The thicknesses of the hole injection layer and the hole transport layer are not particularly limited, but are usually preferably in the range of 1 nm to 5 μm, more preferably 5 nm to 1 μm, and still more preferably 10 nm to 500 nm. The hole injection layer and the hole transport layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.
[0042]
As a method for forming the hole injection layer and the hole transport layer, a vacuum deposition method, an LB method, a coating method by dissolving or dispersing the hole injection transport material in a solvent, an inkjet method, a printing method, a transfer method, etc. Use. In the case of the coating method, the hole injection transport material can be dissolved or dispersed together with the resin component. Examples of the resin component include polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, poly (N-vinylcarbazole), hydrocarbon resin, ketone resin, phenoxy resin, and polyamide. , Ethyl cellulose, vinyl acetate, ABS resin, polyurethane, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin, silicon resin and the like.
[0043]
The material for the electron injection layer and the electron transport layer may be any material having any one of a function of injecting electrons from the cathode, a function of transporting electrons, and a function of blocking holes injected from the anode. Specific examples include fragrances such as triazole, oxazole, oxadiazole, imidazole, fluorenone, anthraquinodimethane, anthrone, diphenylquinone, thiopyrandioxide, carbodiimide, fluorenylidenemethane, distyrylpyrazine, naphthalene, and perylene. Examples include metal complexes represented by cyclic tetracarboxylic acid anhydrides, metal complexes of phthalocyanine, 8-quinolinol, metal phthalocyanines, metal complexes having benzoxazole and benzothiazole as ligands, organic silanes, and derivatives thereof. . Although the film thickness of an electron injection layer and an electron carrying layer is not specifically limited, Usually, the range of 1 nm-5 micrometers is preferable, More preferably, they are 5 nm-1 micrometer, More preferably, they are 10 nm-500 nm. The electron injection layer and the electron transport layer may have a single-layer structure made of one or more of the materials described above, or may have a multilayer structure made up of a plurality of layers having the same composition or different compositions.
[0044]
As a method for forming the electron injection layer and the electron transport layer, a vacuum deposition method, an LB method, a method in which the electron injection / transport material is dissolved or dispersed in a solvent, a coating method, an ink jet method, a printing method, a transfer method, and the like are used. In the case of the coating method, the electron injecting and transporting material can be dissolved or dispersed together with the resin component. As the resin component, for example, those exemplified for the hole injecting and transporting layer can be applied.
[0045]
The material of the protective layer may be any material as long as it has a function of preventing substances that promote device deterioration such as moisture and oxygen from entering the device. Specific examples include metals such as In, Sn, Pb, Au, Cu, Ag, Al, Ti, and Ni, MgO, SiO, and SiO.₂, Al₂O_Three, GeO, NiO, CaO, BaO, Fe₂O_Three, Y₂O_Three, TiO₂Metal oxide such as MgF₂, LiF, AlF_Three, CaF₂Metal fluoride such as SiN_x, SiO_xN_y Nitride such as polyethylene, polypropylene, polymethyl methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, tetrafluoroethylene And a copolymer obtained by copolymerizing a monomer mixture containing at least one comonomer, a fluorine-containing copolymer having a cyclic structure in the copolymer main chain, a water-absorbing substance having a water absorption of 1% or more, a water absorption of 0.1 % Or less of moisture-proof substances.
[0046]
The method for forming the protective layer is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (high frequency excitation ion plate) Coating method, plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, transfer method, etc. can be applied.
[0047]
【Example】
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
[0048]
Example 1
The cleaned ITO substrate is put into a vapor deposition system, and NPD (N, N'-diphenyl-N, N'-di (1-naphthyl) -benzidine) is vapor-deposited to a thickness of 50 nm. A and the above compound (1-2) were co-evaporated to a thickness of 36 nm at a ratio of compound A: compound (1-2) = 17: 1 (mass ratio), and then compound B having the following structure was formed thereon. Vapor deposited to a thickness of nm. A patterned mask (a mask with a light emission area of 4 mm x 5 mm) is placed on the organic thin film, and lithium fluoride is evaporated to a thickness of 3 nm in a vapor deposition system, and then aluminum is evaporated to a thickness of 200 nm. did. Using a source measure unit model 2400 made by Toyo Technica, a constant DC voltage was applied to the EL element to emit light, and the luminance was measured using a Topcon luminance meter BM-8. As a result, external quantum efficiency 1.7%, maximum brightness 6500 cd / m²Of blue luminescence was obtained.
[0049]
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[0050]
Example 2
A light emitting device was fabricated and evaluated in the same manner as in Example 1 except that the above compound (1-22) was used instead of the compound (1-2). As a result, external quantum efficiency is 3.2%, maximum brightness is 9800 cd / m²Of blue luminescence was obtained.
[0051]
Similarly, even when other compounds described above were used, it was possible to obtain a light-emitting element having high external quantum efficiency and maximum luminance and good light emission characteristics.
[0052]
Comparative Example 1
Instead of compound (1-2), light was emitted in the same manner as in Example 1 except that compound C having the following structure similar to the compound of the present invention (tetraphenylbutadiene, compound described in JP-A-5-94875) was used. A device was fabricated and evaluated. As a result, external quantum efficiency 0.6%, maximum brightness 2300 cd / m²Of blue luminescence was obtained.
[0053]
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[0054]
【The invention's effect】
The organic electroluminescence device of the present invention has high luminance and can emit light with high efficiency. Therefore, it can be suitably used in fields such as display elements, displays, backlights, electrophotography, illumination light sources, recording light sources, exposure light sources, reading light sources, signs, signboards, interiors, and optical communications.

Claims (4)

An organic electroluminescent device having at least one organic layer including a light emitting layer between a pair of electrodes, the following general formula (2):
(In the general formula (2) represents R ^21, R ²² and R ²³ are each a substituent, X ²² and X ²³ are each. Representing the unsubstituted carbon atoms) at least a compound represented by the organic layer One organic electroluminescent element characterized by containing one. The organic electroluminescent device according to claim 1, wherein the general formula (2) During, R ^{twenty two} and R ^{twenty three} Are each an aryl group. An organic electroluminescent device having at least one organic layer including a light emitting layer between a pair of electrodes, wherein the following general formula (3):
(In General Formula (3), R ³¹ , R ³² and R ³³ each represent a substituent, and X ³² and X ³³ each represent a nitrogen atom or a substituted or unsubstituted carbon atom) An organic electroluminescent device comprising at least one of an organic layer. The organic electroluminescent device according to claim 3, wherein the general formula (3) During, R ³² and R ³³ Are each an aryl group.